Drafting instrument



April 23, 1968 e. s. DOLGORUKOV DRAFTING INSTRUMENT Original Filed Oct. 5,

United States Patent Ofiice 3,3 78,93 1 Patented Apr. 23, 1968 3,378,931 DRAFTING INSTRUMENT Gregory S. Dolgorukov, Ferndale, Mich.

(407 Fisher Bldg, Detroit, Mich. 48202) Continuation of application Ser. No. 313,698, Oct. 3, 1963. This application Jan. 18, 1967, Ser. No. 610,198 2 Claims. (Cl. 33-4174) ABSTRACT OF THE DISCLQSURE This application discloses an improved lettering guide of the slotted line type, eliminating some serious disadvantages of the previously devised guides of this nature, and particularly the necessity of moving the guide up and down for lettering hyphens and fraction signs in order to center them with respect to whole number and fractions, as is necessary with guides of the prior art in dimensioning operations. The improved lettering guide disclosed herein enables the user to letter in a novel and complete font of engineering lettering based on smallest lettering characters of approximately .16" in height, encircle revision letters with advantageously corresponding circle and to perform Virtually all lettering and dimensioning operations without moving the guide up and down until completing a full line of lettering irrespective of the heights of the characters therein. Furthermore, in one of its aspects the improved lettering guide disclosed herein does not depend on the presence of a guiding straight line edge on its ruler-like body, and therefore may be provided on drafting instruments such as irregular or French curves and sweeps having no straight line edges, and be used on drawings having no positive means identifying its base line. The guides of the construction herein disclosed also provide for drawing circles at the intersection of grid lines usually provided on drafting media such as painted aluminum panels.

The present application is a continuation of my application Ser. No. 313,698 filed on Oct. 3, 1963, for Drafting Instrument.

This invention relates to production of engineering drawings and more particularly to an improved lettering system therefor and an improved instrument for lettering and dimensioning in such improved system.

It has been recognized by those skilled in the art that the methods and costs of production of engineering drawings have changed very little within the last 50 years; that while a substantial decrease in costs have been achieved not only in virtually all other fields of industrial activity but even in other operations relating to drawings, such as their reproduction, the cost of producing an original engineer-ing drawing takes substantially the same amount of time, as far as its routine operations are concerned, as it did 50 years ago, and that drafting room costs continue to increase entirely out of proportion to the savings attained in other fields of industrial activity.

I have found that the above condition resulted in a large measure from adherence to routine practices and particularly to lettering systems having various drawbacks resulting in substantial variances in such systems from drafting room to drafting room, even within the same company, frequently requiring draftsmen to adapt themselves to new requirements not only in changing their employment but even upon being transferred from one drafting room to another. Adapting oneself to new requirements means Working against the force of habit for a considerable length of time, producing fatigue, eyestrain and nervous exhaustion.

The above dimculties have been considerably enhanced by improvements in reproduction of drawings whereby a relatively large drawing such as 24" X 18" and larger can be decreased in size, usually to half size, in the process of reproduction and without any extra cost. Such a possibility, not available in blue printing and very expensive in photostating of large drawings, is of a great advantage in operating drafting rooms. However, the conventional lettering system based on characters of 4;" high for general notes, interfere with the use of such reproductions since decreased to A size, the hand produced lettering and dimensions are not fully legible and the use of such drawing copies leads to serious mistakes, particularly in reading dimensions.

One of the objects of the present invention is to provide an improved lettering system which allows reduction of drawings in size of reduced copies for reference and other purposes and yet to have lettering and dimensioning thereon remain legible while reduced to at least half of its original size.

Another object of the present invention is to provide an improved lettering system in which general notes are lettered or printed in lettering characters of the nature specified in the preceding paragraph with other characters corresponding thereto and particularly capitals, section designations, fractions, tolerances, and the like being so selected as not only to satisfy their intended function and indicate by their respective sizes the nature of the elements they represent but also to have their sizes expressed in decimal fractions composed of not more than two digits.

A still further object of the invention is to provide an improved lettering device enabling its user to letter or print notes and dimensions on drawings in the system specified above without making any measurements and particularly without the necessity of using for such measurements decimal scales divided into hundredths of an inch, which measurements are not only time consuming and productive of eye strain but may necessitate acquiring relatively expensive scales which may not be needed for other drafting operations.

A still further object of the present invention is to provide an improved lettering instrument of the slot line type including a combination slot composed] of a plurality of slot portions of different widths and different arrangements with respect to the guiding edge in connection with which the instrument is used, with the width of the respective slot portions being selected to enable the user to produce lettering characters quickly and precisely in conformity with the above specified system, with the arrangement of the slot portions along the axis of the combination slot being so selected that a line of lettering characters of varying heights, such as may be found in a general note including capitals, fractions, degree signs, revision letters, and the like, can be lettered or printed quickly with a minimum shifting of the guide.

A still further object of the present invention is to provide an improved lettering instrument enabling the user to encircle characters such as revision letters with a circle of one of the diameter sizes provided by the system, or with a two-line circle, without the use of a compass and setting the same for the radius of a required circle.

A still further object of the present invention is to provide an improved lettering and dimensioning instrument of the foregoing nature in which the combination slot satisfies the requirements specified above in an exceedingly short length such as only 6" and, therefore, provide a compact and easily manipulated instrument.

A still further object of the invention is to provide a lettering guide of the slot line type adapted for lettering in the process of drafting operations in which guiding edge parallel to the base line such as provided by a T-square or a straight edge is not available and cannot be used for setting the guide.

Further objects and advantages of this invention will be apparent from the following description and appended claims, reference being had to the accompanying drawings forming a part of this specification, wherein like reference characters designate cor-responding pa in the several views.

FIG. 1 is a-view illustrating my improved lettering guide as it appears to its user.

FIG. 2 is a sectional view taken in the direction of the arrows on the section plane passed through the section line 22 of FIG. 1.

FIG. 3 is a view similar in part to FIG. 1 but showing a modified construction of the guide.

FIG. 4 is a view similar in part to FIG. 3 but showing a further modification of my improved letter guide of the nature illustrated in FIG. 3.

Before explaining in detail the present invention, it is to be understood that the invention is not limited in its application to the details of construction and arrangement of parts illustrated in the accompanying drawing, since the invention is capable of other embodiments and of being practiced or carried out in various ways within the scope of the claims. Also, it is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation.

In the drawing there are shown, by way of example, three lettering guides embodying the present invention. Referring specifically to FIGS. 1 and 2, the lettering guide illustrated therein comprises a body 10 of a rectangular shape, made of a suitable material such as transparent plastic, preferably acrylic plastic. The body 10 has a straight guiding edge 11 provided thereon, which edges is moved in the operation of the lettering guide along the edge of a T-square, a drafting triangle, or a similar instrument.

Parallel to said straight edge ill there is provided a plurality of slots in an end-to-end adjacent arrangement. Said slots are designated in the drawing by the numerals 21, 23, 23, and 24, respectively. The edges of the body at said slots are beveled as indicated at 2 a and 2412 at slot 24. Similar bevels are provided in the remaining slots. The bevels provided along the lower edges of the slots, such as the beveled edge 24a of the slot 24-, are larger than the bevel provided at the beveled edge 24b at said slot 24 along the upper edge thereof. Therefore, while the square portion of the lower edge 24:: is reduced by the bevel to approximately .010, the square portion of the upper edge 24b is reduced by the bevel 24b to approximately .025".

Generally, the square portion of the lower edge of a slot must be as small as is possible to produce uniformity without destroying the bearing strength of the edge, in order to bring the pencil point as close to the lower edge as possible in spite of the inclined position of the pencil. On the other hand, the square portion of the upper edge of the slot must serve as a stop for the pencil point and, therefore, it should extend upwardly for a sufficient height to prevent the pencil point from climbing on the edge. Also, the bevels on the edges of the respective slots are smaller on larger slots in order to leave a higher square portion.

In the embodiment of FIGS. 1 and 2, the four slots provided therein are made in the form of a combination slot, with individual portions thereof 21, 22, 23, and 24 merging longitudinally and thus providing the slots in a form of a single combination slot. Such a construction is more advantageous because of providing the possibility of cutting all four slots without withdrawing the cutting tool. It will be understood, however, that the four slots may also be made individually and have both ends closed. While the latter arrangement complicates somewhat the slot cutting operations by requiring sinking and withdrawing the cutting tool in cutting each separate slot, it

t may, nevertheless, be advantageous under some conditions as increasing the strength of the guide.

Slot 24 has its width so selected as to provide for lettering or printing therethrough lettering characters of approximately .16 high. The width of the slot 23 is selected to provide for lettering therethrough characters of approximately .30 high. Slot 22 provides for lettering characters of approximately .42 high; and, slot 21 for lettering characters of approximately .24" high. By virtue of such a construction, the lettering guide is adapted for producing notes on the drawings in accordance with the improved lettering system disclosed herein.

An important feature of the present invention resides in the lateral arrangement of the slots both with respect to the guiding edge 11 and with respect to each other in order to have lettering characters printed through various slots to be properly aligned with respect to each other, and to provide for printing certain characters, such for instance as fractions corresponding to the characters printed through the basic slot, not only of proper size corresponding to said basic slot but also in proper transverse relation thereto.

The basic slot in the embodiment of FIGS. 1 and 2 is the slot 24 adapted for printing therethrough general notes, including numerals, such as whole numbers, and decimal fractions. In accordance with my improved lettering system these notes lettered through the slot 24 come out .16" high. The slot 23 through which numerals and lettering characters of approximately .30" or .29" high are printed has its lower beveled edge 23a merging with and forming a continuation of the lower beveled edge 24a of the slot 24 and may have substantially the same bevel thereon. However, the upper edge 23b of said slot 23 extends above the edge 24b of the slot 24, whereby the slot 23 is adapted for printing therethrough larger numerals such as part numbers as well as capitals for the letters printed through the slot 24, should it be desired to capitalize some words of the notes.

The slot 22 has its upper beveled edge 22b merging with and forming a continuation of the upper beveled edge 23b of the slot 23, while its lower beveled edge 22a extends below the edges 23a and 24a to provide such width for the slot 22 as to print therethrough the numerators and denominators of fractions corresponding in size and transverse space relationship to the whole numbers printed through the slot 24.

The slot 21 has its upper beveled edge 21b merging with and forming a continuation of the beveled edges 22b and 23b, while its lower beveled edge 21a extends downwardly to satisfy three further requirements: first, to give the slot 21 the width to letter or print therethrough characters of approximately .24 or .23" high, and also to have a line such as line 25 drawn against the edge 21a as a guide line extend substantially along the continuation of the center line of the slot 22 and 24. By virtue of such a construction the fraction sign for the fractions printed through the slot 22 can be drawn by using the lower edge of the slot 21 as a guiding edge and the line so drawn would come substantially in the middle of the whole number printed through the slot 24. For instance, in lettering the fraction 4 illustrated in the drawing, the whole number 4 is first printed through the slot 24. Then the guide is moved to the right to bring the slot 21 on the right side of the numeral 4 so printed and the fraction sign is drawn against the edge 212a. Thereupon the guide is moved for a short distance to the left bringing the slot 22 into such a position as to have the inclined line 25 extend through the middle of said fraction sign, and the numerator 5 and the denominator 16 are then printed through said slot 22, with the line 26 as a center line, thus completing the fraction. At this point it may be mentioned that the inclined lines such as line 26 are provided on the slot body and used as a center line on which the fraction is written giving it proper inclination.

The slot 21 must also satisfy a third requirement,

namely, to be so located in the direction transverse to the remaining slots that the line such as line 27 drawn against the upper edge 24b of the slot 24 as a guiding edge lies substantially on the continuation of the center line of said slot 21 and, therefore, comes substantially in the middle of lettering characters printed through said slot 21. By virtue of such a construction the slot 21 is adapted to print therethrough lettering characters as required for section designations which are of the roman type for distinctiveness and are hyphenated. Such hyphen provided between the lettering characters B-B is designated by the same numeral 27 as the line in FIG. 1 drawn at the upper edge of the slot 24 since in the use of the guide it will be the same line.

It will be understood in view of the foregoing that with each of the slots requiring that two or three conditions of space relationship be satisfied with respect to one or more slots presents a problem the successful solution of which determines the quality of the guide and ease of its use as well as compliance with the prescribed requirements presented 'by my improved lettering system.

On the body of the lettering guide, and preferably on the underside thereof to eliminate parallax, there are marked a plurality of vertical lines such as 28 and of inclined lines such as 29 extending similarly to line 26 at an angle of 67 /z to serve as reference lines to give the lettering characters proper inclination. The three -horizontal lines 31, 32, and 33 running parallel to the slot are provided at such distances from the slot 24 that when the line 31 is placed over the top edge of a printed line of lettering characters the slot 24 becomes located under said line of lettering characters to letter the next lower line at a distance of .12". Placing the line 32 over the top of the previously written line arranges the slot at a distance of .16" from the bottom of the previously printed line, while the use of the line 33 in a similar manner arranges said slot at a still further distance. Placing such lines over the bottom of the previously written line instead of its top is used when fractions, capitals, and larger numerals are included in the line of characters.

In accordance with the invention, there are provided on the body of the guide two circular apertures 35 and 36 through which circles for encircling the revision letters (i.e. letters identifying revisions or changes made in a drawing) printed through slot 24 is done. Both apertures have their centers on the continuation of the center line of the slot 24 and, therefore, after a revision letter is printed through said slot 24, moving the guide to the right and arranging it around the letter permits encircling it with one circle or two concentric circles, as required, and in such a manner that the letter is arranged in the middle of the circles. The aperture 35 is adapted to draw therethrough circles of approximately .32" in diameter, while the aperture 36 is adapted for drawing therethrough circles of .38" in diameter. By virtue of such a construction virtually all requirements for revision letter circles are satisfied. In operation, the letter is first printed through the slot 24. Then the guide is moved to the right, as mentioned, one of the apertures depending on the requirements is arranged around the letter, and the circle is then drawn. When a double circle is required, it is preferable to draw the smaller circle first and then move the guide to the left and arrange the aperture 31 concentrically with the drawn circle. Placing with the pencil point faint trial marks before drawing the circle may be done to ensure concentricity.

The lengths of the respective slots 21-24 is of importance. In order to ensure compactness of the guide I arrange the entire combination slot within approximately 6" of length between the end vertical lines 28. The slot 24 is the longest, since it is desirable to letter or print therethrough full words of the general notes without moving the guide after printing a few letters only. I prefer to make such slot approximately 3 /2" in length. The

slot 23 through which larger numerals are printed can be made approximately in length since the numerals of that size are printed slower and usually consist of a few digits only. The slot 22 through which. fractions and particularly large characters are printed. may be approximately 1" in width. The slot 21 should be at least 1" in length in order that the section designation consisting of two letters spaced at some distance with a hyphen between them be printed therethrough without moving the guide (for printing the letters themselves). This would ensure the uniformity of both letters. Hyphenating the section designation, i.e. providing the hyphen 27, can, of course, be done with moving the guide to the left as explained above.

FIG. 3 illustrates a lettering guide for my improved lettering system as it is used in drafting operations wherein the guiding edge such as provided by a T-square or a strung straight edge is not available and the drafting is done with the use of grid lines as reference lines. Such lines are usually provided on large sheet aluminum panels coated on the top surface with a coat of paint of white or other suitable color. Such panels are used in automobile body and aircraft fusilage designing instead of paper. In accordance with the present invention the slots are arranged parallel to the spacing lines and by placing one of such spacing lines on one of the grid lines or a line parallel thereto lettering operations can be performed through the slot. If the lines are parallel to the longitudinal edge of the guide body, the slots will be parallel to that edge also, but being parallel to that edge is not a requirement in this construction. In such type of drafting, fractions are seldom used and, therefore, shifting of the guide is reduced to a minimum. Accordingly, most of the general notes, dimensioning and section designation can be done with only two slots such as slots 41) and 41. The slot 40 is provided for printing therethrough lettering characters of .16" high and the slot 41 lettering characters of approximately .24.25 high.

An aperture 42 having its center arranged on the continuation of the center line of the slot 40 provides for drawing therethrough circles of approximately .32" in diameter and can be used for encircling revision letters printed through the slot 40. An aperture 43 provided in the body is adapted for drawing therethrough circles of approximately .625 in diameter usually placed with their centers at the intersection of two grid lines with identifying numerals such as 5, 10, 15, 20, etc. to identify the grid lines placed within the respective circles. The center of the aperture 43 is on a line of the upper edge 40]) of the slot 40. In use, the slot is placed to have the edge 40b along a grid line which enables the user to align the aperture at the intersection of the grid lines to draw the circle. Of course, usual cross lines may be provided at both apertures 42 and 43. However, since marking cross lines is done in one machine and cutting the apertures is done in another machine, the problem of registry difficult in any situation becomes very serious with pieces of plastic. On the other hand, since cutting the slots and the apertures is more conveniently done in the same machine, the problem of registry is thus eliminated and does not arise.

FIG. 4 illustrates a guide of the same general nature as the guide illustrated in FIG. 3 and used substantially for the same applications but having its apertures 52 and 53 arranged in spaced relation with respect to the separate slots 50 and 51.

The slot 50 is adapted for printing therethrough lettering characters of approximately .16" high. The aperture 52 adapted for drawing therethrough circles of approximately .32 in diameter is arranged to have its center on the continuation of the center line of said slot 50 in order to use said aperture 52 for encircling the characters printed through the slot 50.

The slot 51 which is arranged above the slot 50 and is separated from it by a bridge portion 55 is adapted for printing therethrough lettering characters of approximately .24".25" in height. The aperture 53, adapted for drawing therethrough circles of approximately .625" in diameter, is arranged on the center line of said slot 51. A dotted line 56, which can also be used as a spacing line, represents the center line of the slot 51 and may run through substantially the entire length of the guide. When drawing circles through the aperture 53 is desired, the dotted line 56 is placed over one of the grid lines as explained above. The numerals in the circle so drawn are printed through the slot 51, which slot can also be used for section designations. In spacing the note lines, the line 56 is placed over the top or bottom of the previously written line or over a grid line or a line parallel therethrough. It shall be noted that a dotted line to be placed over a solid line on the drawing provides for a greater precision than a solid line, since the undesirable effect of the thickness of the solid line on the guide is thus eliminated. For instance, should the line on the guide be rather thick but the line on the drawing extremely thin and faint, portions of such thin line on the drawing seen through the breaks in the dotted line enable the user to arrange the guide to have the line in the drawing pass through the middle of the thickness of the line on the guide.

By virtue of my improved lettering system and the construction of the lettering guides disclosed above, the objects of the present invention listed above and numerous additional advantages are attained.

I claim:

1. A lettering guide for lettering in four sizes of lettering characters forming a complete font based on the smallest characters thereof being of .16 nominal height, said guide comprising a fiat elongated body having at least one straight squared locating and guiding side, four slots provided in said body in adjacent end-to-end arrangement and each having a lower edge and upper edge extending parallel to said guiding side, the distance between the upper and lower edges of the first of said slots being in the range of .160".170", with the second slot being immediately adjacent to said first slot and having its lower edge forming a straight line continuation of the lower edge of said first slot, the distance between the upper and lower edges of said second slot being in the range of .27".29", the distance between the upper and lower edges of said third of said slots being in the range of .40".42 and with its upper edge forming a straight line continuation of the upper edge of said second slot, the distance between the upper and lower edges of the fourth slot being in the range of .21-.23" and having its upper edge forming a straight line continuation of the upper edges of said second and third slots; the lower edge of said fourth slot extending substantially along the center line of said third and said first slots to provide for drawing fraction signs extending substantially centrally with respect to fractions lettered through said third slot as well as substantially centrally of the whole numbers and other characters lettered through the first slot, and with lines drawn on a drawing against the upper edge of the first slot as a guide forming hyphens for the characters lettered through said fourth slot.

2. The lettering guide defined in claim 1, with the body thereof being provided with two coaxial circular apertures of different diameters and having their centers lying on the continuation of the lower edge of the fourth slot and of the center line of said first slot, said apertures providing for drawing therethrough circles encircling concentrically and with a predetermined clearance lettering. character drawn through the first slot only, and useable to encircle the same selectively with a single line circle and with a double line circle.

References Cited UNITED STATES PATENTS 2,016,985 10/1935 Carlson 33l74 X 2,379,791 7/1945 Dolgorukov 33174 2,512,852 6/1950 Dolgorukov 33-174 FOREIGN PATENTS 251,664 12/ 1948 Switzerland.

OTHER REFERENCES Publication: Catalog, Drawing Instruments and Templates, Dolgorukov Manufacturing Co., Detroit, Mich., 2nd edition, 1956, page 5.

SAMUEL S. MATTHEWS, Primary Examiner.

LEONARD FORMAN, Examiner. 

